Reversing switch



L. F. MEUNIER ETAL REVERSING SWITCH Filed Feb. 15, 1945 5 Sheets-Sheet 1 ATTORNEY 1944- L. F. MEUNIER EI'AL 2,361,901

REVERSING SWITCH Filed Feb. 15, 1943 5 Sheets-Sheet 2 INVENTORS ATTohNEY Oct 1944- L. F. MEUNIER ET AL 2,361,901

REVERS ING SWITCH Filed Feb. 15, 1943 5 Sheets-Sheet 3 1 .5 T a b4- 76 15 M [E 19447 L. F. MEUNIER ETAL 2,361,901

REVERSING SWITCH Filed Feb. 15, 1943 5 Sheets-Sheet! ATTORN EY 1944- 1.. F. MEUNIER ETAL 2,361,901

REVERSING swncn Filed Feb. 15, 1945 5 Sheets-Sheet 5 71: 12.. v 'Tuzyilw.

INVENTORS Zia/V F. Mia/we? ATTORNEY Patented Oct. 31, 1944 REVERSING swrrorr Leon F. Meunier and Albert H. Funk, Cleveland, Ohio, assignors to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application February 15, 1943, Serial No. 475,886

(01. 2o-o s 14'Claims.

This invention relates to electrical apparatus, and particularly to reversing switches of the kind used in machines and tools, such as coal mining drills, embodying an electrically operated reversible motor.

The general object of the invention is to improve upon the reversing switch disclosed in the patent to L. F. Meunier and C. J. Dresser, 1,817,013 granted August 4, 1931. The device of that patent taught that a single control member may be utilized for starting, stopping and reversing the switch; that locking means may function to compel opening of the line before the switch can be conditioned to change the direction of rotation of the motor; and that the switch, except for the control membeiimay be totally enclosed to guard against ignition of mine gases. The structure of the patented switch aforesaid included separate sets of contacts mounted respectively on a movable shaft and a stationary terminal block, the shaft being rotatable to engage and disengage the contacts and shiftalble longitudinally to change the relation of the contacts and so cause reversal of the current flow. The control member operated the shaft and also had movement in two senses, rotary and longitudinal.

Specific objects of this invention are to make the switch of more compact design and durable of construction; to simplify its manner of operation; and to'add to'the element of safety in its use by preventing operation of the switch when it is undergoing servicing, such as fuse replacement.

A feature of the invention is the elimination of axial motion from the movements of the control member and the contact carrying shaft, and the modification of the mounting forthe terminal block to permit axial movement thereof. Results of this change, in which the terminal block rather than the shaft is shifted when reversing, are that the overall width of the switch is reduced and the possibility of lead breakage materially lessened since the leads are flexed in only one plane. Another feature of the invention is the provision of means for imparting rotary movement to the contact carrying shaft and longitudinal movement to the terminal block in response to an oscillating motion of the control member, the control member being turned in one direction from a normal or off position to start the motor running in a forward direction and turned in the opposite direction from normal to start the motor running in a reverse direction.

A further feature is that the control member is made a part of an operating shaft assembly which must be removed before access may be had to the switch for servicing and which can be removed only when the current is shut off from the motor.

Other objects and structural details of the invention will be apparent from the following de scription when read in conjunction with the accompanying drawings, wherein:

Fig. l is a view in front elevation of a switch embodying the present invention;

Fig. 2 is a fragmentary view partly in front elevation and partly in section showing the means for preventing detachment of a cover plate closing the front of the switch;

Fig. 3 is a detail View of the manipulative control member, its off-normal control positions being indicated in dotted outline;

Fig. 4 is a View of the switch in vertical section, this view being enlarged with respect to Fig. 1 and taken substantially along the line 44 of Fig. 5;

Fig. 5 is a View in cross section taken substantially along the line 5-5 of Fig. 4;

Fig. 6 is a detail view, in plan, of the terminal block, the mounting therefor, and the cam means for shiftin the block;

'Fig. '7 is a fragmentary detail view of the contact apparatus in operating position;

Fig. 8 is a detail View in cross section of the movable contact carrier, being taken along the line 88 of Fig. 4;

Fig. 9 is a wiring diagram illustrating the electrical connections between the contacts and the motor; and

Figs. 10 to 13 are position views of the means for rotating the contact carrying shaft and for shifting the terminal block, these views showing respectively the position the parts assume with the switch Off, the position of the parts during forward rotation, the position of the parts with the switch conditioned for a reversal of the current flow but with the circuit still open, and finally the position of the parts during reverse operation.

Referring to the drawings the switch is contained in and supported by a casing l5 adapted to be mounted on the toolor machine which it is to control in such manner that theoperating parts of the switch are totally enclosed. For operating the switch there is provided-outside the front of the casing a control member in the form of a hand operated pointer l6 rotatabl in opposite directions from the vertical Offposition of Fig l to control stationslmarked by the designations For. (forward) and Rev. (reverse) on the casing. With the control member l6 in normal position (at the designation Olf) the electrical circuit passing through the switch stands open and the tool is inactive. Upon turning the member to the right hand control station the circuit is closed, the flow of current at this time being such as to obtain rotation of the motor in a first or forward direction. Movement of the member l6 from normal to the left hand control station causes initially a change in the switch elements conditioning the circuit for a reversal of current flow and then closing of the circuit to effect rotation of the motor in a second or reverse direction.

Current is supplied to the switch by a cable I! which extends into the casing through an elongated bushing |8 (see also Fig. 5). The cable ll serves as a conduit for leads which, inside the casing, are connected to ground and to an insulated terminal block IS. The block l9, as shown in Fig. 4 and in the diagrammatic illustration Fig. 9, has fixed thereto a set of four contacts 2|, 22, 23 and 24 separated by barriers 25. Adapted to engage the contacts 2| to 24 are a set of three movable contacts 26 connected through a fuse 21 to the motor, indicated generally at 28 in Fig, 9. The separate sets of contacts have a relation which can be varied by longitudinal shifting of the block |9 in order that the movable contacts 26 will, when operated, alternatively engage terminal contacts 2|, 23 and 24 or terminal contacts 2|, 22 and 23. According to the wiring of the circuit, in the former instance the flow of current will be such as to cause forward rotation of the motor while in the latter instance the current flow is altered in a manner causing a reverse rotation of the motor.

As shown in Figs. 4 and 5 the movable contacts 26 have the form of blades yieldingly attached to supports 29, which supports are clamped to a carrier 3| arranged parallel to the terminal block I 9. Referring also to Fig. 8 the carrier 3| is protected from direct contact with the supports 29 by a covering of insulating material 32 and is rotatably mounted on a shaft 33. The ends of the shaft 33 are journaled in screw-threaded studs 34 set in internal bosses on the casing IS. The relative rotary motion permitted the carrier 3| and shaft 33 is utilized to obtain a snap action in the engagement and disengagement of the contacts 26 with the terminal block. Secured to the shaft 33 is a bail assembly comprised of arms 35 and 35 and a connecting rod 31, the arms being keyed to the shaft at points beyond the opposite ends of the carrier 3|. The arm 35 has an angularly disposed portion 35 carrying a transverse pin 38. The pin 38 is engaged by the notched upper end of a plunger 39, the lower end of which projects through an opening in the turned over end of an arm 4| secured to the contact carrier 3|. A coil spring 42 surrounds the intermediate portion of the plunger 39 and is confined in a state of tension between the bent end of arm 4| and a flange 43 on the plunger. The disposition of the pin 38 with respect to the opening in arm 4| is such that the spring 42 urges the arm and carrier 3| to which it is attached in a clockwise direction as viewed in Fig. 5, a direction tending to disengage the movable contacts from the terminal block. When the shaft 33 is rotated in a clockwise direction, as b lifting the bail assembly attached thereto, the pin 38 moves into and beyond a position of alignment with the opening in arm 4|. In response to movement of the pin toward such position the plunger 33 is pressed outward alongside a stop 44 which is engaged by the plunger as the pin 38 moves past center. As the shaft 33 continues to turn plunger 39 is withdrawn until it no longer engages stop 44 whereupon spring 42 operates to swing arm 4| in a counterclockwise direction or in a direction to engage the contacts 26 with the terminal block. The parts assume at the end of this motion the postion shown in Fig. 7. The lower end of the arm 4| extends within a U-shaped bracket 45 which thus defines the opposite limits of movement of the contact carrier.

The assembly of elements on the shaft 33 further includes barriers 46 between the contact blades, and the assembly fills the space between the journal studs 34 thus inhibiting longitudinal movement of the carrier 3|. The contacts 26 move only in a rotative sense and the leads at tached thereto accordingly are flexed in only one direction.

The terminal block I9 is fastened by means of screws 41 to a bracket 48. The bracket 43, as shown in Fig. 5, curves upward over the terminal block and has an upright portion 48 slidably connected to an internal wall 49 of the easing |5 by pin in slot means made up of slots 5| and screws 52. The terminal block is movable between the limits set by the pin in slot means and in the extremes of such movement places either the pair of contacts 23 and 24 or the pair of contacts 22 and 23 in line with the respective middle and right hand contacts 26 (as viewed in Fig. 4). Terminal contact 2| is broader than the others and so is engaged by the left hand contact 26 in either position of the block. The terminal block thus is also movable in only one sense, but in this case the motion is reciprocating and parallel to the axis of the rotatable contact carrier,

The manipulative control member l6 represents the sole operating means of the switch, the oscillating motion thereof being used both to shift the block l9 and to turn the shaft 33. Referring to Fig. 5 the member 6 is keyed to a shaft 53 which has a bearing in the wall of the casing IS with one end outside the casing and the other end on the inside. The inner end of shaft 53 is reduced in diameter and is received in a recess 54 in a second shaft 55 rotatably mounted in the internal wall 49. The telescoping portions of the shafts 53 and 55 are keyed together so that the shafts rotate as a unit in response to adjustment of the control member l6. Preventing separation of the shafts is an elongated bolt 56, the shank of which is passed through a longitudinal bore in the shaft 53 and into screwthreaded engagement with the shaft 55 at the bottom of recess 54. The head of the bolt is adapted to engage the manipulative member I6 through a washer 51, and, when so engaged, holds the member and the shafts 53 and 55 together as a unitary assembly. In order that the assembly may be held in each of its control positions detent mechanism is provided including a disc 58 nonrotatably mounted on the front end of the shaft 55. The front surface of the disc 58 is engaged by a spring pressed plunger 59 in the wall of the casing and adapted to seat in complementary recesses 6| in the disc. The recesses 6| are so spaced about the disc that the arrival of the control member |6 in any of its off, forward or reverse positions brings one of the recesses 6| opposite the plunger 59.

The shaft 55 projects rearward of the internal wall 43 and has fastened to its projecting end, as

of its center position to the other. In the course.

by a keyed connection, a cam plate 62. The plate 62 thus is rotatable with and is part of the manipulative operatin assembly. On the rear surface of the cam plate 62, near the outer edge thereof, is a rearwardly facing boss 63 to which is pivotally connected one end of a link 64. The other end of the link is attached to the rod 31 of the bail assembly on shaft 33 so that oscillation of the cam plate serves to raise and lower the bail assembly and thereby rock the shaft 33. As shown in Figs. 4 and 6 the boss 63 is offset or to one side of the vertical axis passing through shaft 55. As a result that part of the movement of the cam plate 62 during which the boss 63 approaches and moves from'a position beneath the shaft 55 is a lost-motion period so far as its effect on the shaft 33 is concerned. The front surface of the plate 62 lies adjacent the upright portion 48 of the terminal block supporting bracket 48. The portion 48 has fixed thereto a stud 65 (see Fig. 6) facing the cam plate 62 and carrying a follower roller engaged in a cam slot 66 in the plate 62. As seen in Figs. 4 and 10 to 13 the slot 66 has upper and lower arcuate portions 61 and 68 connected by a vertical portion 69. With the follower stud 65 positioned at the top of vertical portion 69 (the position shown in Figs. 4 and 10) rocking motion of the cam in a right hand or clockwise direction is accomplished without effect on the plate 48, since the follower stud 65 ridesin arcuate portion 61. However, motion of the cam in a left hand or counterclockwise direction from the Fig. 4 position causes a longitudinal shifting movement of the bracket 48 as the stud 65 is cammed to the right by the vertical portion 69.

The parts are so arranged that when the manipulative control member I6 is in the vertical position of Figs. 1 and the cam plate 62 occupies the position shown in Fig. 10. At this time the bail assembly controlling shaft 33 is lowered or down and the shaft accordingly is set to a position holding the contacts 26 disengaged from the terminal block. Also the terminal block supporting bracket 48 is in its extreme left hand position by reason of the location of the follower stud 65 at the top of the vertical slot portion 69, the switch being thus conditioned to effect forward rotation of the motor. Now if the member I6 i turned toward the right, a corresponding or clockwise movement is effected of the plate 62 which attains theposition shown in Fig. 11 as the control member reaches its right hand control station. As the cam plate turns, the link 64 is drawn upward and raises the bail assembly comprising arms 35 and 36 and rod 31 to rock shaft 33. Near the end of such movement the contact carrier 3| moves quickly from the position of Fig. 5 to the position of Fig. 7, and the movable contacts 26 engage the terminal contacts to close the circuit and start the motor. Return of the control member I6 to its starting point restores the parts to normal, the contacts 26 being disengaged in response to the lowering of the bail assembly and the consequent return movement of the carrier 31. When it is desired to reverse the direction of rotation of the motor the control member I6 i turned leftward from normal. The control member is permitted a greater travel in this direction than when turned to the right and accomplishes its function in two steps, illustrated respectively in Figs. 12 and 13.

During the first part of this motion the cam plate 62 moves independently of the bail assembly .on shaft 33 as the boss 63 is carried from one side of this movement the vertical portion 69- of the cam slot 66 acts on the follower stud to shift the terminal block to its extreme right hand position and so changes the relation of the terminal contacts 2| to 24 with respect to the movable contacts 26. The end of the first step of movement places the follower stud 65 at the top of lower arcuate portion 68 of slot 66, and, as the motion of the cam plate continues, the stud 65 rides in the lower arcuate portion holding the terminal block locked in its right hand position During this motion of the cam plate, which represents the second step of the reversing stroke, the link 64 is drawn upwards as before to rock the shaft 33 and cause engagement of the contacts. Upon return of the manipulative control member the above operations are repeated in inverse order, the contacts being disengaged before shifting of the terminal block takes place.

The fuse 21 is mounted in spring clips H on a board 12 fastened to internal bosses on the easing. Access to the interior of the casing, for the purpose of replacing a blown fuse or servicing of the switch, is obtained through the removal of a cover plate 13 closing a central opening in the front of the casing. Cover plate 13 has a threaded connection with a bushing 14 and has a projecting flange portion engageable with the outside wall of the casing. The closure effected by the cover plate 13 is a tight, dustproof, and flame-proof connection.

In the interests of safety it is undesirable that the switch should be operated when the cover plate 13 i removed. Therefore, the cover is locked against detachment from the casing by a plate 16 which is mounted on the shaft 53 and overlaps the flange 15, preventing the cover from being screwed out of the bushing 14. The plate 16 is keyed to the shaft 53 and held against axial movement thereon by the hub of control member I6 which presses the plate to a shouldered seat on the shaft. The locking plate lies between the main wall of the casing and an overhanging lip portion 11 thereof, and by engagement with the portion 11 is adapted to prevent the shaft 53' from being removed from the casing. The upper portion of the plate 16 has a cut-away shape best seen in Fig. 2, while lip portion 71 has an opening 18 of similar shape (see Fig. 1). In the Ofi" position of the control element l6 the plate 16 registers with opening 18 and may be withdrawn from looking position through said opening.

When, the motor running in a forward or reverse direction, the operator discovers that the switch is in need of servicing he first returns the control member l6 to its vertical or off position. By this action the electrical contacts are disengaged to open the circuit, and the looking plate 16 is brought in line with the opening 18. Then the bolt 55 is turned in a direction to unscrew it from the shaft 55, whereupon the assembly comprising the bolt, the shaft 53, control member l6 and locking plate ('6 is free for axial movement out of the casing. A spring clip 19 on the bolt 56 prevents withdrawal thereof independently of the shaft 53. The removable shaft assembly is connected to the cover plate 13 by a link 8|. Thus, after the bolt 56 has been loosened the cover may be turned in an unscrewing direction and, as it is removed, will carry the shaft assembly also out of the casing. The shaft 55 remains in the switch but is not accessible for operation and is held in its set position of adjustment by the co-action of disc 58 and detent plunger 59.

What is claimed is:

1. An electrical switch, comprising first and second sets of contacts, said first set being movable and adapted to engage said second set to close the circuit and initiate a flow of current, actuating means for opening and closing the circuit by moving said first set of contacts toward and from said second set, shifting means for changing the relation of said sets of contacts to cause a fiow of current alternativel in forward and reverse directions, a manipulative control member for operating said actuating means and said shifting means and having a neutral position in which said sets of contacts are diseng ged, and connection means between said control member and said actuating means and said shifting means operable in response to motion of said control member in one direction from neutral position first to move said shifting means and then to move said actuating means.

2. A single control electrical switch, comprising separate sets of contacts capable of relative movement in a first sense during which they are engaged and disengaged to start and stop the fiow of current, and capable of relative movement in a second sense to change the relation of the contacts and thereby condition the switch for reversal of the current flow; a manipulative control member rotatable in opposite directions from a normal to oil-normal positions; and means for automatically effecting relative movement between said sets of contacts successively in the second and first senses in response to rotary movement of said control member to one of said off-normal positions, said latter member constituting a single control means from which alone, when manipulated, the relative movements of the sets of contacts in both senses are exclusively derived.

3. An electrical switch, comprising separate sets of contacts capable of relative movement in a first sense during which they are engaged and disengaged to start and stop the fiow of current, and capable of relative movement in a second sense to change the relation of the contacts and thereby condition the switch for reversal of the current flow; a manipulative control member rotatable in opposite directions from a normal to offnormal positions; means for effecting relative movement in the first sense between said sets of contacts in response to movement of said control member to said off-normal positions, said means being arranged to provide a lost-motion period during the movement of said controlmember to one of said oft-normal positions; and means acting in said lost-motion period to effect relative movement in the second sense between said sets of contacts.

4. An electrical switch according to claim 3, characterized in that said last-named means comprises a cam and follower mechanism, the follower being attached to one of said sets of contacts and the cam being movable with said control member and adapted to impart a longitudinal shifting motion to said one set of contacts during a predetermined portion of the movement of said member.

5. An electrical switch, comprising separate sets of contacts capable of relative movement in a first sense during which they are engaged and, disengaged to start and stop the flow of current, and capable of relative movement in a second sense a flow of current in a forward direction when engaged; means responsive to movement of said control member in either direction from normal for causing engagement of said contacts; and means responsive to movement of said control member in one direction from normal for conditioning said contacts for a reversal of current fiow before said contacts are engaged.

iii

6. An electrical switch, comprising separate sets of contacts capable of relative movement in a first sense during which they are engaged and disengaged to start and stop the flow of current, and capable of relative movement in a second sense to change the relation of the contacts and thereby condition the switch for reversal of the current flow; a manipulative control member for effecting relative movement between said sets of contacts in both said first and second senses, said control member being movable in only one sense; and independent means operable in a timed relation by said control member for moving said sets of contacts in said first sense and in said second sense.

'7. An electrical switch, comprising separate sets of contacts capable of relative movement in a first sense during which they are engaged and disengaged to start and stop the fiow of current, and capable of relative movement in a second sense to change the relation of th contacts and thereby condition the switch for reversal of the current flow; and a manipulative control member ior effecting relative movement between said sets of contacts in both said first and second senses, said control member being movable in opposite directions from a normal position and acting during one direction of movement to efiect relative motion between said sets of contacts in said first sense only and acting during movement in the opposite direction to effect motion between said contacts successively in said second sense and said first sense.

8. An electrical switch, comprising separate sets of contacts, one set being mounted on a shaft rotatable to efiect engagement and disengagement of said contacts, and the other set being mounted on a block shiftable to change the relation between said separate sets of contacts and so condition the switch for reversal of the current flow; first and second independent means operative respectively to rotate said shaft and to shift said block; and a manipulative control member acting when moved to one control position to actuate only said first independent means and acting when moved to another control position successively to actuate both said second and first independent means.

9. Anelectrical switch, comprisin separate sets of contacts, one set being mounted on a shaft rotatable to effect engagement and disengagement of said contacts, and the other set being mounted on a block shiftable to change the relation between said separate sets of contacts and so condition the switch for reversal of the current flow; independent means operative respectively to rotate said shaft and to shift said block; and a manipulative actuating member for said means movable alternatively in one direction to rotate said shaft Without shifting said block and in another direction to shift said block and then rotate said shaft.

10. An electrical switch, comprising first and second sets of contacts so related as to permit a flow of current when engaged and to interrupt such flow when disengaged, a manipulative control member movable in opposite directions from a normal to off-normal positions, connection means between each control member and said sets of contacts for engaging said sets of con-- tacts upon movement of said control member to said off-normal positions and for disengaging said contacts in response to movement of said control member to normal position, and means for changing the relation of said sets of contacts in response to movement of said control member toward and from one of said off-normal positions to provide for reversal of current flow.

11. An electrical switch, comprising separate sets of contacts, one set being mounted on a shaft rotatable to effect engagement and disengagement of said contacts, and the other set being mounted on a block shiftable to change the relation between said separate sets of contacts and so condition the switch for reversal of the current flow, said shaft and said block being disposed parallel to one another; a cam plate rotatable about an axis at right angles to said shaft and said block; linkage connecting said cam plate to said shaft and arranged to rock said shaft in response to an oscillating motion of said cam plate in either direction from a normal position, said linkage providing a lostmotion period at the start of the movement of said cam plate in one direction from normal during which period said plate moves independently of said shaft; and a connectionbetween said cam plate and said block arranged to shift said block during said lost-motion period.

12. An electrical switch, comprising separate sets of contacts; means rotatabl to engage and disengage said contacts and to change the relation of said sets of contacts to provide for reversal of the current flow; a casing totally enclosing said contacts and said rotatable means, said casing including a cover plate removable to permit access to the switch for servicing; a rotatable operating shaft extending through the easing into operative engagement with said rotatable means and manipulative from outside the casing to actuate said means; means on said shaft for locking said cover plate against removal from the casing; means for disengaging said operating shaft from said rotatable means to permit withdrawal of said shaft to a position releasing said cover plate from said locking means; and means preventing withdrawal of said shaft to'said position except when said rotatable means is adjusted to a position in which said sets of contacts are disengaged.

13. An electrical switch, comprising separate sets of contacts and means for engaging and disengaging said contacts to open and close the circuits; a casing totally enclosing said contacts and the engaging and disengaging means therefor, said casing including a cover plate removable to permit access to the switch for servicing; means for locking said cover plate against removal; a rotatable operating shaft extending through the easing into operative engagement with said engaging and disengaging means and manipulative from outside the casing to actuate said means, said shaft being capable of being withdrawn from operative engagement with said engaging and disengaging means; and means for disabling said locking means in response to the withdrawal of said shaft.

14. An electrical switch according to claim 13, characterized by means for preventing withdrawal of said operating shaft from operative engagement with said engaging and disengaging means except when said means is in a position holding said contacts disengaged and the circuit open.

LEON F. MEUNIER. ALBERT I-I, FUNK. 

